Project Summary Health disparities among sexual and gender minority people exist across the lifespan, and are increasingly well-documented, yet gaps remain in our basic understanding of how health varies within these groups. This was emphasized in the Institute of Medicine's 2011 report on LGBT health, which pointed specifically to the need for more research among bisexual populations. While bisexual men experience notable health disparities related to both outcomes and access to care, we know very little about the unique risk factors that bisexual- identified men experience. The minority stress model posits that minority groups face stressors associated with their minority status that are unique and additive to everyday life stressors. The majority of work related to sexual minority stressors and health has presumed that experiences of lesbian, gay and bisexual groups are the same. Additionally, there is little work assessing the health effects of daily-level, identity-based stressors and health among SGM populations. The proposed study will address these gaps in the literature, using a novel, multi-method approach. Through qualitative interviews, use of daily electronic diaries over 28 consecutive days, and survey measures, we will test the hypothesis that racially diverse bisexual men who more frequently report microaggressions will have poorer mental and physical health outcomes than bisexual men who less frequently report microaggressions. Aims are: 1)Identify the characteristics of racially diverse bisexual men's microaggressive experiences, e.g., context, content and source, including their responses to such experiences; 2) Determine the frequency and source of sexual orientation and racial/ethnic microaggressions among bisexual men and test their association(s) with daily mental and physical health; 3) Assess lifetime stressors that may influence associations between MAs and daily and lifetime mental and physical health. This study is a companion to a similar study among bisexual women, and will allow for cross- gender comparisons. This preliminary exploration of within-group differences can significantly advance our knowledge of the risk factors associated with health disparities among racially diverse bisexual men. Findings will be critical for informing directions for future research and practice through the identification of relevant research questions and/or foci for preventative interventions.